Direction and timing of dispersal of Scirtothrips dorsalis (Thysanoptera: Thripidae) on select ornamental host plant species in south Florida

Abstract

Chilli thrips, Scirtothrips dorsalis Hood (Thysanoptera: Thripidae), is a troublesome pest of agronomic, vegetable, fruit, and ornamental crops. Scirtothrips dorsalis dispersal and monitoring were evaluated under field and greenhouse conditions in Homestead and Apopka, Florida, in 2007. A field test examined dispersal from Knock-Out® rose, Rosa ‘Radrazz’ (Rosaceae), onto green buttonwood, Conocarpus erectus L. (Combretaceae), and ‘Emerald Green’ schefflera, Schefflera arboricola Forst & Forst ‘Emerald Green’ (Araliaceae). Fewer adults were caught in traps set north, east, or south than west of rose plants corresponding to the average wind direction. Scirtothrips dorsalis flights increased during the morning to early afternoon, peaked about 9:00 a.m. to 2:00 p.m. EST, then decreased to almost no flights by 8:00 p.m. Warmer temperature and lower humidity corresponded to more adults caught per hour with most flights occurring after the accumulation of 300 degree-hours. ‘Emerald Green’ schefflera was preferred over, or may have been less repelling than, green buttonwood. Yellow sticky-card traps were most effective when placed downwind of suspected host plants, and field sites may need more traps per unit area and longer exposure periods than greenhouse sites. These findings may help managers to better monitor and manage S. dorsalis.